Fluid Mechanics Questions and Answers – Total Pressure & Vertical Plane Surfa…

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Total Pressure & Vertical Plane Surface Submerged in a Liquid”.

1. Does total pressure takes into the account force exerted by the fluid when it is in the dynamic motion?
a) Yes
b) No
c) Depends on the conditions
d) Depends on the type of Motion
View Answer

Answer:b
Explanation: Total pressure is defined only for the static fluid at rest. There is no dynamic component as no motion is involved.

2. Can centre of pressure for a vertical plane submerged surface be ever be above centre of Gravity
a) Yes
b) No
c) It can be above in cases where the surface height is very large
d) None of the mentioned
View Answer

Answer: b
Explanation: Centre of pressure always lies below the centre of gravity. In certain cases it may coincide but it can never be above the centre of gravity.

3. Which principle is used for calculating the centre of pressure?
a) Principle of momentum
b) Principle of conservation of energy
c) Principle of balancing of momentum
d) None of the mentioned
View Answer

Answer: c
Explanation: We balance the moment in order to calculate the position of centre of pressure.
advertisement

4. In a vertically submerged plane surface, pressure at evbery point remains same
a) True
b) False
View Answer

Answer: b
Explanation: Pressure at every point is different as the depth of different point from is different.

5. The magnitude of total pressure and centre of pressure is independent on the shape of the submerged plane surface.
a) True
b) False
View Answer

Answer: b
Explanation: For differently shaped surfaces, the area and hence position of centroid will be different. Hence, the magnitude of total pressure and centre of pressure is dependent on the shape of the submerged plane surface.
Free 30-Day Python Certification Bootcamp is Live. Join Now!

6. What is the variation of total pressure with depth for any submerged surface if we neglect variation in the density?
a) Linear
b) Parabolic
c) Curvilinear
d) Logarithmic
View Answer

Answer: a
Explanation: Total pressure is given by,
F=w*a*y
hence, F ∝ y i.e linear relation.

7. A pipe line which is 6 m in diameter contains a gate valve. The pressure at the centre of the pipe is 25 N/cm2. If the pipe is filled with specific gravity 0.8, find the force exerted by the oil upon the gate.
a) 7.06 MN
b) 14.12 MN
c) 3.53 MN
d) 28.24 MN
View Answer

Answer: a
Explanation: ĥ=p/ρg
=250000/9.81*800
=31.855 m
F=wAĥ
=9.81*800*9*π*31.855
=7.06 MN.

8. Determine the centre of pressure on an isosceles triangle plate of base 6m and altitude 6m when it is immersed vertically in an oil of specific gravity 0.75. The base of the plate coincides with the free surface of oil.
a) 6 m
b) 3 m
c) 9 m
d) 12 m
View Answer

Answer: b
Explanation: ŷ=I/Aĥ + ĥ
I=bh³/36
ŷ=36*2/18 + 2
=3 m.

9. A tank contains water upto a height of 0.5 m above the base. An immiscible liquid of specific gravity 0.75 is filled on the top of water upto 1.5 m height. Calculate total pressure on side of the tank.
a) 17780.61 N/m2
b) 35561.22 N/m2
c) 71122.44 N/m2
d) 8890.31 N/m2
View Answer

Answer: a
Explanation: F = F1 + F2 + F3
F=w*A*ŷ
F= 8277.18+5518.12+3985.31
= 17780.61 N/m2.
advertisement

10. A circular opening, 6m diameter, in a vertical side of a tank is closed by a disc of 6m diameter which can rotate about a horizontal diameter. Calculate the force on the disc. The centre of circular opening is at the depth of 5 m.
a) 1.38 MN
b) 2.76 MN
c) 5.54 MN
d) 7.85 MN
View Answer

Answer: a
Explanation: F=w*A*ŷ
=9.81*1000*3.142*32*5
=1.38 MN.

Sanfoundry Global Education & Learning Series – Fluid Mechanics.

To practice all areas of Fluid Mechanics, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
I’m Manish - Founder and CTO at Sanfoundry. I’ve been working in tech for over 25 years, with deep focus on Linux kernel, SAN technologies, Advanced C, Full Stack and Scalable website designs.

You can connect with me on LinkedIn, watch my Youtube Masterclasses, or join my Telegram tech discussions.

If you’re in your 40s–60s and exploring new directions in your career, I also offer mentoring. Learn more here.